Wound healing is a complicated process in which the skin repairs itself after injury. The normal wound healing process can be broadly classified into three stages namely the inflammatory, proliferative and maturation phases. The inflammatory phase that lasts up to two days involves an orderly recruitment of cells to the wound area, which is followed by proliferative phase lasting up to 6 days. In this phase, the fibroblasts, keratinocytes and other cells in the wound bed begin to actively proliferate to close the wound. The maturation phase follows the proliferative phase, will take about two weeks, by which time the wound will be completely healed by restructuring the initial scar tissue.
However, certain wounds are problematic and do not follow the normal time table for the healing process, will take longer time to heal. Thus the problematic wounds associated with additional attention, pain management and with increased costs.
Re-epithelialization is a critical step in wound healing; in which epidermal keratinocytes laterally migrate to close a wound. However, in chronic wounds, keratinocyte migration is blocked and the wounds remain open, causing more harm to the patients.
Oxygen has a significant role in wound healing, being essential to provide the additional energy source for the repairing process. It has been shown in numerous clinical studies that in typical wound, partial pressures of oxygen are markedly reduced and may be the rate limiting process in wound repair. Also, supplemental oxygen has been shown to enhance healing dependent on dose and frequency. Therefore, the availability of oxygen may, in fact, be one of the rate limiting steps in early wound repair.
Further, most wounds heal rapidly and efficiently but the results are not perfect, as the healing process leaves scar on the skin. Scar tissue is less flexible than normal skin and can be cosmetically disfiguring affected area.
As is evident from the above, the two major goals of wound healing (tissue repair) which includes rapid healing and complete reconstruction of the damaged area without leaving scar.
Apart from the synthetic would healing compositions, also, there is literature available on biocompatible compositions in the prior art for wound healing and methods of use thereof.
US20150094273 discloses synergistic pharmaceutical composition comprising an antibiotic and sophorolipid, to effectively combat the problem of antibiotic resistance by increasing the permeability of the antibiotic drugs across the outer membrane of bacteria. The sophorolipid being amphiphilic in nature can span through the structurally alike cell membrane and facilitate the entry of antibiotic drug molecules.
Article titled “Silk sericin ameliorates wound healing and its clinical efficacy in burn wounds” by Pornanong Aramwit et al. published in Archives of Dermatological Research, 2013, 305(7), pp 585-594 reports evaluate the effect of silk sericin, a protein from silkworm cocoon, on scratch wound healing in vitro. For applicable result in clinical use, author also study the efficacy of sericin added to a standard antimicrobial cream, silver zinc sulfadiazine, for open wound care in the treatment of second-degree burn wounds.
Project title “Purified rhamnolipids/sophorolipids biomedical applications including cutaneous wound healing” by Prof. Ibrahim Banat, Prof. Christopher Mitchell, Prof. Roger Marchant reports biomedical applications of rhamnolipids/sophorolipids including cutaneous wound healing.
Article titled “Silk sericin and its applications: A review” by M N Padamwar et al. published in Journal of Scientific & Industrial Research, 2004, 63, pp. 323-329 reports silk consists of two types of proteins, silk fibroin and sericin. Sericin contributes about 20-30 percent of total cocoon weight. It is characterized by its high content of serine and 18 amino acids, including essential amino acids. There are different methods of isolation of sericin from silk thread. Solubility, molecular weight, and gelling properties of sericin depend on the method of isolation. It has wide applications in pharmaceuticals and cosmetics such as, wound healing, bioadhesive moisturizing, antiwrinkle and antiaging.
U.S. Pat. No. 5,981,497 discloses utilization of sophorolipids as therapeutically active substances or cosmetic products, in particular for the treatment of the skin. This invention relates to a new use of a sophorolipidic compound, of pharmaceutically acceptable salts of the acidic form of the sophorolipid, and of the ester of the deacetylated sophorolipidic acid form as therapeutically active substances in a method for therapeutic treatment of the human or animal body, and more particularly as an activator of macrophages, as a fibrinolytic agent, as a healing agent, as a desquamating agent, and as a depigmenting agent.
Article titled “Antioxidant activities of silk sericin from silkworm Bombyx Mori” by Jin-Bo Fan et al. published in Journal of Food Biochemistry, 2009, 33(1), pp 74-88 reports investigation of the free-radical-scavenging activity and antioxidant activity of silk sericin. Silk sericin was prepared from silkworm Bombyx mori and its ability to scavenge hydroxyl, superoxide and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals was determined by Electron Spin Resonance (ESR) and ultraviolet spectrophotometry, respectively. The antioxidant activities of the silk sericin, including lipid peroxidation in the linoleic acid system, reducing power and ferrous-ion-chelating ability, were evaluated. The results showed that silk sericin had a strong scavenging capacity for hydroxyl, superoxide and DPPH radicals. The results also showed that silk sericin had potent antioxidative activity on the peroxidation of linoleic acid. The reducing power and ferrous-ion-chelating ability of silk sericin were significant. These results indicated that silk sericin from silkworm B. mori was a natural antioxidant with potent antioxidative activity.
Article titled “The effects of sericin cream on wound healing in rats” by Aramwit P. et al. published in Bioscience, Biotechnology, and Biochemistry, 2007, 71(10):2473-7 reports sericin has good hydrophilic properties, compatibility, and biodegradation, it can be used as a wound-healing agent. Author evaluated the effects of sericin on wound healing and wound size reduction using rats by generating two full-thickness skin wounds on the dorsum. Group 1 animals were treated with Betadine on left-side (control) wounds and, with 8% sericin cream on right-side (treated) wounds. Group 2, cream base (formula control) and 8% sericin cream (treated) were topically applied to left-, and right-side wounds respectively. Sericin-treated wounds had much smaller inflammatory reactions, and wound-size reduction was much greater than in the control throughout the inspection period. Mean time in days for 90% healing from sericin-treated wounds was also much less than for cream base-treated wounds. Histological examination after 15 d of treatment with 8% sericin cream revealed complete healing, no ulceration, and an increase in collagen as compared to cream base-treated wounds, which showed some ulceration and acute inflammatory exudative materials.
Article titled “Preparation of gel film from Bombyx mori silk sericin and its characterization as a wound dressing” by Teramoto H et al. published in Bioscience, Biotechnology, and Biochemistry, 2008 December; 72(12):3189-96 reports sericin is a highly hydrophilic protein family acting as the glue in Bombyx mori silk. In order to apply sericin as a wound dressing, a novel sericin film named gel film was prepared by a simple process without using any chemical modifications: sericin solution was gelled with ethanol into a sheet shape and then dried. Infrared analysis revealed that the sericin gel film contained water-stable beta-sheet networks formed in the gelation step.
CN103990175 discloses a pharmaceutical controlled release bilayer nano-fiber wound dressing and preparation method. A two-layer wound dressing nanofibers controlled drug release function, wherein: the water-soluble natural polymer is sericin, hyaluronic acid, sodium alginate, water-soluble chitosan, in order to improve the water-soluble natural polymer can be spun to introduce co-spun polymer polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polylactic acid (PLA), in which the natural polymer and co-polymer spinning the mass ratio of 4:1˜1:10.
PCT Application WO2013112875A1 discloses Wound dressings with enhanced gas permeation and other beneficial properties. A first embodiment of this invention provides a wound dressing comprising a wound dressing substrate including gas vesicles, rhamnolipids, and sophorolipids. A second embodiment provides a wound dressing as in the first embodiment, wherein the wound dressing substrate includes a wound dressing hydrogel. A third embodiment provides a wound dressing as in either the first embodiment or the second embodiment, wherein the wound dressing hydrogel comprises a polymer selected from the group consisting of polyvinyl alcohol, alginate, chitosan, carboxyethyl chitosan, methylcellulose, gelatin, soy protein, wheat protein, xanthan gum, gum arabic, polyacrylamide, polyalcohols, polysaccharides, polyamines, proteins, or mixtures thereof. Article titled “Silk sericin as a moisturizer: an in vivo study” By Padamwar M N et al. published in Journal of Cosmetic Dermatology, 2005, 4(4), pp 250-257 reports Sericin gels were prepared using sericin solution and with pluronic and carbopol as stabilizers. The gels were applied on the skin of healthy human volunteers and its moisturizing efficiency was evaluated by measuring the skin hydroxyproline content, impedance, TEWL, and scanning electron microscopy (SEM) results.
In the light of the foregoing, it is evident that although many methods have been proposed and tested to promote wound healing and limit scarring; however, cost-effective methods and compositions are still desired to address the above out-standing issues.